HDPE等温结晶中液-固转变的流变特性  

Rheological Properties of Liquid-solid Transition in Isothermal Crystallization for High-density Polyethylene

作　　者：陈青[1] 范毓润[1] 李文春[2] 郑强[2] 

机构地区：[1]浙江大学流体传动及控制国家重点实验室 [2]浙江大学高分子科学与工程学系,杭州310027

出　　处：《高等学校化学学报》2006年第2期365-368,共4页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20274041);国家杰出青年基金(批准号:50125312)资助

摘　　要：研究了高密度聚乙烯(HDPE)等温结晶过程中液-固转变的流变行为.发现在等温结晶过程中,旋转流变仪的平行板上会产生法向拉应力;在结晶初期,此应力会快速松弛;一定时间后,呈现出积聚并迅速增加的现象.针对此现象提出了一种新的静态测试方法,即利用由结晶导致的体积收缩测量法向拉力.对动态测试和静态测试方法下的流变行为进行比较发现,动态测试适用于结晶速率较慢的体系,而静态测试则适用于结晶速率较快的体系.相对于前者而言,后者具有不干扰被测试样结晶行为的优点.The rheological properties of liquid-solid transition during the crystallization for high-density polyethylene（HDPE） was investigated through the static and dynamic rheological measurements. It is found that with the crystallization proceeding, a tensile force upon the parallel-plates is induced by volume contraction of the sample. In the case of static test with the motionless parallel plates, this tensile force relaxes quickly in liquid states, while starts to accumulate after certain time. Accordingly, a new method to determine the liquidsolid transition depending on the static tensile force is proposed. A comparison between it and the classic dynamic one for detecting liquid-solid transition evidences that the dynamic method is preferred to slow crystallization, and static method is more appropriate for the crystallization at moderate rates. Furthermore, the latter has the advantage of no disturbing the crystallization behavior of HDPE before the transition.

关 键 词：高密度聚乙烯 等温结晶 液-固转变 流变特性 

分 类 号：O631[理学—高分子化学]